Antithyroglobulin Test

If your doctor has diagnosed you with idiopathic infertility (infertility due to causes unknown) you may be pondering whether now is the time to pack it in and give up on ever getting pregnant. But don't be so hasty—there are still diagnostic tests that can help your physician figure out what it is that is standing between you and having a baby. One of these tests is the antithyroglobulin test.

The purpose of the antithyroglobulin test is to measure the levels of the antibodies produced by your body in response to the proteins your thyroid gland manufactures. Recurrent miscarriage is often due to high levels of these antibodies as is unexplained infertility.

Thyroglobulin is a protein produced by the thyroid gland. The thyroid helps to regulate the many hormones responsible for controlling your metabolism, heart rate, and a variety of other bodily functions.

Battling Intruders

In the case of people in good general health, the body produces antibodies to battle germs and other intruders that can make us fall ill with cold viruses or the flu. But for a significant number of people, the body sees healthy normal thyroglobulin cells as enemy intruders and begins to manufacture antibodies to do battle with them. Antithyroglobulin is one of these antibodies. Its purpose is to obliterate the thyroglobulin protein cells manufactured by the thyroid. The production of antithyroglobulin, unchecked, will lead to the eventual destruction of your thyroid gland.

Antimicrosomal antibodies that can also attack the thyroid are sometimes produced at the same time as antithyroglobulin antibodies. When these two antibodies appear in the bloodstream, they are lumped together as "antithyroid antibodies."

The link from antithyroglobulin to infertility was discovered only in recent times. Experts found that antithyroglobulin interferes with the implantation of the fertilized egg. As the embryo tries to cling to the uterus, these antibodies are released. The antibodies act like toxins and the fledgling pregnancy ends in miscarriage.

Doubled Risk

Women who tend to high blood levels of antithyroglobulin often have trouble getting pregnant. Should they succeed in conceiving a child, there is twice the risk of miscarriage when compared to women who don't have the antibodies. Of those women who have experienced recurrent miscarriages, 30% have high blood levels of antimicrosomal or antithyroglobulin antibodies. Recurrent IUI and IVF failures have also been attributed to the presence of antithyroid antibodies.

If your test results for antithyroglobulin come back positive, your doctor may decide that this may be, at least in part, a factor in your infertility woes. There are medications that can help bring down the levels of these antibodies, for instance dexamethasone and prednisone. After a course of treatment, you may just find yourself with child!